AR15 Thumb Hole Stock

Being a long time bolt action shooter, I got used to a thumbhole stock, dunno why, but it felts great in my hand.
I've been looking for a Thumb Hole Stock for my AR15, but have never seen one, till now
I know it looks strange, but I was wondering if you know where can I find one, or have heard about and AR15 Thumb Hole Stock
Thanks